My Hydrogen / Methane Breath Test Was Negative, How Can I Still Have SIBO?

My Hydrogen / Methane Breath Test Was Negative, How Can I Still Have SIBO?

The hydrogen / methane breath test is used to diagnose if you have SIBO. You still have a large amount of bloating, gas, and stomach discomfort, but yet your breath test results were negative.

Is it possible to still have SIBO, if your breath test results were negative?

The hydrogen/methane breath test is a non-invasive fasting test in which your doctor has you breathe into a machine that monitors excess hydrogen or methane that is released by the opportunistic bacteria in your small intestine. You are either given glucose, dextrose, or lactulose, during the test to consume, and the test input is collected at twenty-minute intervals for at least three-five hours. If you produce at least twenty ppm of hydrogen or three ppm of methane during the test, you test positive for an active SIBO infection (but even a result of twelve ppm hydrogen should be treated at the very minimum). If your hydrogen and methane are flat lined or do not rise during the test, you may have the third type of SIBO, hydrogen sulfide producing bacterial overgrowth.1

It is debatable about which is test is better, lactulose or glucose? Bacteria have to ferment lactulose in the intestines for it to be absorbed by the body. Glucose is easily broken down by the microbiome or directly absorbed by the gastrointestinal system. The use of glucose as a test marker may give a false negative reading because at least seventeen feet of the small intestine may not be tested. Finally, in people with IBS-D, the glucose might reach the cecum and begin fermentation sooner, creating a false positive SIBO result in people with strictly colonic overgrowth.2 3 4 5 6

There are some issues with the use of lactulose that might produce some false negatives. Not all bacteria/archaea that would cause an overgrowth ferment lactulose, which may cause a false negative test result. Lactulose increases bowel transit time, which may skew the test results. It might be best to get both tests done (glucose and lactulose) to determine bacterial overgrowth. Finally, it may be best to have a bowel transit test done as well, like a sitz marker test to determine one’s motility, and how long it would take the test substances to reach the colon.7 8 9 10

People can still have symptoms of SIBO, and both tests come back negative. How can that be?

Again, not every overgrowth of bacteria in the gut will contain bacteria that produce hydrogen, so these tests could be inaccurate in determining SIBO. There is also no unified medical interpretation of SIBO breath tests, therefore, a doctor might perceive it to be normal, and it is not. If your values do not rise during the test, you may have hydrogen sulfide producing bacterial overgrowth in the small intestine. I recommend using the guidelines of hydrogen/methane breath interpretation by the leading SIBO expert, Dr. Allison Seibecker.11 12 13

I recommend getting a GI Effects performed by Genova Diagnostics through your gastroenterologist. I can help interpret the results of your bacterial culture, lactoferrin levels, pH, and antibody levels to determine if you have SIBO. Contact me for Health Coaching if you are interested.

It is best to tackle your SIBO if you have many of the symptoms of SIBO, instead of relying on breath test results. If you are not any better within a month of following the FODMAP diet and SIBO protocols then SIBO was either not your problem in the first place (might be a yeast issue instead or SIYO), or the protocol was not strong enough to eliminate some hardy bacteria like MAP or Klebsiella. There is no public test for MAP currently (outside of specific testing at a university or hospital pathology laboratory), but Klebsiella can be tested for by using the GI Effects.

  1. Hi John!

    I just had a SIBO test with lactulose. But I’m not sure if the Test is POSITIVE or NEGATIVE, I’m very confused. What do you think?

    • Positive for hydrogen in the beginning, and positive for methane throughout. You might have upper gut hydrogen dysbiosis and methane dominant SIBO.

      • Thank you very much for your response John. I will follow your protocol. The clinic in which I did the Test, the only thing that it says is (NEGATIVE – No malabsorption or intolerance is detected against the administered sugar. “LACTULOSE”) But it does not say if I have SIBO or not. Also to see that the levels of Methane do not perform any PEAK as it usually happens, If not it goes down with the passage of time, that made me doubt if it was POSITIVE or NEGATIVE. And my doctor says that the SIBO does not exist

  2. So, go to see a REAL WORLD medical DOCTOR!🙆

    • I have already gone several times. I’m from a small town in Spain and when you talk to doctors here about things like SIBO or Leaky Gut, they treat you like crazy. They say that does not exist. That’s why I asked here

  3. Hi Jon,

    My friend just called me and asked if he should take the antibiotic after he gets the results. I told him I only took an antibiotic for the strep I got after taking an antifungal drug, lufenuron, and it kind of undid the good effect of the antifungal. I did it again later and got a staph throat infection, which I fought off using colloidal silver and DGL. I never felt better—except after doing ANOTHER lufenuron round and dealing with the subsequent sore throat after that. It seems like I get better every time. All symptoms have subsided to a minimal level (weakness, cold appendages, acid reflux, silent reflux, gallbladder inflammation, pancreatic inflammation, etc.) but I still get some gas, bloating, and digestive distress. Perhaps there’s a residual SIBO in there. In any case, I think yeast can be just as big of an issue. It’d be nice if they had a definitive test that could account for the yeast in there as well, but I don’t see that happening anytime soon. Until then, I guess more of the inflammational symptoms can be attributed to Candida (and as you know, I consider acid reflux to be from inflammation, because the gas/bloating that I get do not cause reflux in me—could be a combo of built-up gas AND inflammation?), and the gas could be more from SIBO? Something to think about. However, if you use any kind of antibiotic, which they’ll probably put you on, you’re leaving yourself open to candida again, so I think you should use the probiotic/fermented food crowd-out method of rebalancing your gut instead.

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